Tetrakisazo dyestuffs



Patented July 8, 1952 UNITED STATES PATENT OFFICE TETRAKISAZO DYES'TUFFS Walter Anderau, Basel, Switzerland, assignor to Ciba Limited, Basel, Switzerland, a Swiss firm No Drawing. Application December 19,1947, Se-

rial No. 792,853. In Switzerland January 10,

7 Claims. (01. 260-166) I in which R1 represents a benzene residue containing a hydroxyl group and in ortho-position thereto a carboxyl group, and R2 represents a benzene residue in which the azo-group and the diazotisable amino-group are in the 1:4-position relatively to one another, and which contains an alkyl-O-group in ortho-position with respect to the diazotisable amino-group, in an alkaline medium with a disazo-dyestuff of the general formula l lI=NR -N=N-Ra in which R3 represents a benzene residue containing a hydroxyl group and in ortho-position thereto a carboxyl group, and R4 represents a benzene residue in which the azo-groups are in the 1:4-position relatively to one another.

The amines of the above formula used as starting materials in the present process can be obtained, for example, by coupling the diazo-compound of an amino-hydroxybenzene ortho-carboxylic acid with a 1-amino-2-allmxybenzene capable of coupling in the 4-position. The amino-hydroxybenzene ortho-carboxylic acid as also the 1-amino-2-alkoxybenzene may contain further substituents. Such substituents in the case of the amino-hydroxybenzene orthocarboxylic acids, may for example be alkyl groups such as the methyl group, alkoxy groups such as the methoxy group, halogen atoms such as bromine and especially chlorine, nitro groups, sulphon-amide groups, etc. Thus, for example, one may start from 6-amino-4-nitro-l-hydroxybenzene-Z-carboxyllc acid. In some cases it is of advantage to use 4-amino-1-hydroxybenzene- Z-carboxylic acid or a derivative thereof which contains in the 6-position one of the substituents named above; as examples of such compounds there may be mentioned ,6-methy1-, 6-chloroand 6 nitro -4 amino l hydroxybenzene Z-carboxylic acid.

Among the 1-amino-2-alkoxybenzenes unsubstituted in the 4-position, which serve as coupling components for making the amines of the formula R1N:N--R2--NH2, there may be used 'pri-" marily 2-ethoxyand 2-methoxy-1-aminobenzones, which contain-in the 5-position a substituent which favours the coupling, for example,'

an alkyl, especially a methyl, group,or an alkoxy groupsuch as anethoxyor methoxy-group." If it is desired to use l-amino-Z-alkoxybenzenes which are free from further substituents, such as 1 amino 2 methoxybenzene or 1 amino 2 ethoxybenzene,

w-methane-sulphonic acids.

The coupling of the diazotised amino hydroxybenzene-ortho-carboxylic acid with the l-amino- 2-alkoxybenzene capable of coupling in the 4- position to produce the starting material of the above formula R1-N=NR2NH2 to be used in the invention may be carried out in the usual manner in itself known in an acid medium, preferably a medium rendered acid with acetic acid.

A number of the amines of the formula serving as starting materials in the present invention can be made by coupling a diazotised l-amino-3-alkoxybenzene which contains in the 4-position a group convertible into an Nil-Iz-group,-

for example, a nitro or acylamino group, vwith a hydroxybenzene-ortho-carboxylic .acid capable of coupling, and converting the nitro or, acylamino group in the resulting azo-dyestuff into an Nl-lz-group. By this method it is possible to prepare, for example, the following amine serving as,

a starting material in the present invention: 4- amino 3 methoxy 4' hydroxy 1:1 -azobenzene-3'-carboxylic acid-fi-sulphonic acid.

The disazo-dyestuifs also serving as starting materials in .the invention and having the gen- H033 -NHa such compounds are advane tageously used in the form of their so-called' 3 in which R3 and R4 have the meanings given above, can be obtained, for example, by coupling a diazo-compound of an amine of the general formula H fR AQ with 2-amino-5 hydroxynaphthalene 7-su1phonic acid in an acid medium, advantageously a medium rendered acid with a mineral acid. The amines of the formula in which R3 represents a benzene. residue containing a hydroxyl group and. in orth -position thereto a carboxyl group, andjm represents a benzene residue in which the azo group and the diazotisable amino group are in the 1:4-position relatively to one another, may be obtained in the same manner as the amines of the formula the-residue R4 maybe free fromfurther substituents as is the case, for example, with 5'- chloroor S methyI-I or 5' nitr'o-4-amino-4 hydroxy-l :1' azobenzene-3T-arboxylic acid and with 4 amino 4'' hydroxy -T 1:1? azobenzene- 3- 'carboxylic-acid, which must be especially men- 7.

tioned in this-connection, or the residue R4 may contain further substituents. Among the substituted amines ,of the above formula good results may be-obtained principally with those which correspond to the general formula in which one of. the substituents X2 and X3 represents hydrogen, alkylor alkoxy and the other represents. alkyl or alkoxy, such, for example,

as 2-methyl-4-amino-5 methoxy- 2frhydroxy-5'- nitro-l 1'-azobenzene-3'-carboxylic"acid. There are especially suitable as starting material those amines of the above mentioned formula in which R2; represents the residue of a 'l-hydroxyben- V zene-.-2-carboxyli c acid bound in the *i-position to the azo-group. The latter residuemay'be free from further substitutents, or may contain a further substituent, advantageously in the 6-position, such, for example, as an alkyl group such as methyl, an alkoxy group such as methoxy, a halogen atom such as chlorine, etc. As examples of such amines there may be mentioned 2-' methoxy-, 2:5-dimethoxy-, 2 -methoxy-5-ethoxyor 2 methyl 5 methoxy 4 amino 4' hydroxy-l:1-azobenzene-3'-carboxylic acid and al- 4 so substitution products of these compounds which contain in the 5'-position, for example, a methyl group, a chlorine atom, a nitro-group, a methoxy group or a sulphonamide group.

The diazotisation of theamines of the general formula, a

R1--N=N--R2NH2 used as starting materials in the invention and of-the amines of the general formula 7 used for preparing the starting materials of the general formula III=NR4N=NR:

may be carried out, for example, by the so-called indirect method, that is to say, by combining a solution containing an alkali salt of such an amine and also the necessary quantity of nitrite with a dilute acid solution containing a quantity of acid, especially hydrochloric acid, in excess of the theoretical quantity.

Thegcoupling of the diazo-compound of the amine of the general formula R1N=NR2NH2 with the disa-zo-dyestuff of the general formula is conducted in an alkaline medium, advantageously rendered alkaline with an alkali carbonate, if desired, with the addition of an agent favouring the coupling reaction or an agent capable of binding acid such as pyridine, ethanolamines, etc.

The tetrakisazo-dyestuifs obtainable by the present invention are new and correspond to the general formula I|Q'=NR4N#NR1 I in which R1 and R3 each stand for a benzene radical containing a hydroxyl group and in or- ,tho-position thereto a carboxyl group, R2 stands for a benzene radical in which the two azogroups are in the 1:4'-position relatively to one another and which contains an alkyl-O-group in ortho -position with respect to the azo-group,

bounfd; ftO the naphthalene nucleus, and R4 stan ds'for a benzene radical in which the azogroups are in the 1 :4-p0sition relatively to one, another.

These dyestuffs aresuitable for dyeing avery' wide variety of.materi als,'for example, animal fib es such a WO L- nd athe an p cially for dyeing or printing" materials contain-- kaline medium, under atmospheric or superatmospheric pressure, with or Without additions such as salts of inorganic or organic acids such as tartaric acid, agents capable of binding acid or favouring the formation of complexes, such as pyridine. The production of metal, especially copper, compounds in substance is of special value in the case of those metal-free dyestuffs which have too weak an aifinity and when the metalliferous dyestuifs still possess adequate solubility. In the case of those dyestuifs obtainable by the invention which possess only-few groups imparting solubility and have a sufficient or good aflinity for cellulose fibres in the metalfree condition, they may, with advantage, be treated with an agent yielding metal by known methods on the fibre or in part on the fibre and in part in the dyebath. It is of advantage, for example, to use the process of U. S. Patent No. 2,148,659 in which first the dyeing and then the treatment with an agent yielding metal are carried out in the same bath. As agents yielding metal there come into consideration advantageously those which are stable towards alkaline solutions, such as complex copper tartrates and the like.

In some cases especially valuable dyeings can be obtained by working in accordance with the process in which dyeings or prints produced with the metal-free dyestuffs are'after-treated with aqueous solutions which contain basic condensation products of formaldehyde with compounds HOOC containing in the molecule at least once the atomic grouping or with compounds capable of being easily transformed into compounds containing said atomic grouping as, for instance, cyanamide, and which solutions also contain water-soluble copper compounds, especially complex copper compounds. Such processes are described, for example, in French Patent No. 929,599. Such dyeing processes may lead to valuable results above all when dark, for example, deep black, tints are to be produced with the dyestuffs obtainable by the invention.

The dyestuffs obtained by the present process are distinguished from known dyestuffs with similar constitution such as, for example, those described in French Patent No. 874,616, in that they serve to make coppered dyeings of especially pure, deep black tints which are considerably faster to light.

The following examples illustratethe inven- Ea'antple 1 25.7 parts of 4-amino-4-hydroxy-1:1'-azobenzene-3-carboxylic acid are diazotized with 6.9 parts of sodium nitrite in the presence of 25 parts of hydrochloric acid of 30 per cent. strength, and coupled with a freshly prepared weakly acid suspension of 23.9 parts of 2-amino- 5-hydroxynaphthalene-7- sulphonic acid. The coupling which lasts for several hours can be finished by neutralising the free mineral acid with sodium acetate or by heating the mineral acid suspension. The resulting dyestufl' suspension is rendered alkaline with 20 parts of sodium carbonate, then heated to 70 C., and the disazodyestuff is precipitated by the addition of. so-

dium chloride and separated by filtration. The

dyestuff paste is dissolved in 800 parts of water at 50 0., mixed'with 25 parts of sodium alkaline solution of the disazo-dyestuff obtained as described above. The resulting tetrakisazo-dyestuff precipitates to a very great extent. After a little time the whole is heated to C., 100 parts of sodium chloride are added in order to obtain the dyestuif in a good filterable form, and the dyestuff is separated by filtration and dried. It is a black powder and corresponds in its free acid state to the formula HOaS- O-CHa It dissolves with a black-blue coloration in water, in dilute alkalis and in concentrated sulphuric acid. Vegetable fibres andregenerated cellulose are dyed grey to black tints from baths cone after-coppering process, for example, by the process in which the dyeings produced with the metal-free dyestufi are after-treated in aqueous solutions containing basic condensation prodtion, the parts and percentages being by weightz ucts of formaldehyde with compounds which contain in the molecule at least once the atomic grouping and water-soluble copper compounds.

NH, 0 on 7'. A dyestufi having. similar properties and corresponding, in its free state to the formula isobtained by diazotising 30.1 parts of Z-methyl- 4-amino-5-methoxy 4'-hydroxy 1:1'-azobenzene-3'-carboxylic acid, instead of 25.7 parts of 4-amino-4-hydroxy-1:1-azobenzene 3' carboxylic acid, coupling in an acid medium with 23.9 parts of 2-amino-5-hydroxynaphthalene-7- sulphonic acid, and in other respects working in the manner described above;

Example 2 25.7 parts of 4-amino4'-hydroxy-1 l -azobenzene-3'-carboxylic acid are diazotised' with.6.9 40

rendered. alkaline with 20 partsof sodium carbonate, themheated'to 70 C., and the disazodyestuiftv is precipitated .by the addition of sodiumchloride and separated'byfiltration; The' dyestuffjpaste .is dissolved in. 800Tparts of 'water: at

50? 0., mixed with'28zpartsof sodium carbonate,.1

and cooled to .02' C. bythe addition ofice;

31.7 parts of 1 the 'monoazo-dyestufi, obtained, by couplingpthe diazo-compound of 153 parts of 4-amino-1-hydroxybenzene2-carboxylic acid.

Withf.15;3 parts of l-aminoe2':5-dimethoxybene zene'in an acid medium; are'suspended .in 300 parts of water, brought into solution by neutralisation with caustic soda solution, and diazotized at 0-3 C. in. the presence of 25 parts of hydrochloric acid .and 6.9 parts of. sodiuminitrite. 5

O-GH:

The C011- 45 8 The. resulting diazo. compound is coupled with the alkalineisolution of'the disazo-dyestufl obtained as described above. The Y tetrakisazo-dyestuff, which. is formed after a short time, precipitates. After a little-time the .whole is heated to-7'0 C., parts of sodium'chloride are added in order to obtain the'dyestufl' in a good filterable form, and' the dyestuif is separated by filtration and dried. The dyestufi thus obtained is a black powder and corresponds in its free acid state to the: formula It dissolves with a blackish coloration in water, in dilute alkalis and in concentrated sulfuric acid. Vegetable fibres and regenerated cellulose fibers are dyed greenish grey to black tints from baths containing sodium sulfate which are neutral or have been rendered weakly alkaline with sodium carbonate. The dyeings are rendered fast to Washing and light by treatment with agents yielding metal, especially copper salts.

Especially valuable bloomy black tints which are fast to washing and light are obtained by dyeing cotton with this dyestufl by the single bath or 2-bath after-coppering process, for example, bythe process in which the dyeings produced with the metal-free dyestufl." are aftertreated in aqueous solutions containing basic condensation products of formaldehyde with compounds which contain in the molecule at least once the atomic grouping and water-soluble copper compounds.

A dyestuff having similar properties and correspending in its free acid state to the formula 100 parts of cotton are entered at 50 C. into a dyebath consisting of 4000 parts of water, 2 parts of anhydrous sodium carbonate and 2 parts of the dyestufi obtainable as described in the first paragraph of Example 1, the temperature is raised to 90-95 C., in the course of 20 minutes, 30 parts of crystalline sodium sulphate are added, and dyeing is carried on for 30 minutes at 90-100 C. The whole is then allowed to cool to about 70 C., and the further treatment consists of one of the procedures described under (a), (b) and below.

(a) The dyeing is rinsed with cold water and treated for /2 hour at 50 C. in a bath containing 4000 parts of water, 3 parts of crystalline copper sulphate and 1 part of acetic acid. The goods are then rinsed and dried. A deep black dyeing is obtained of good :fastness to light and having very good properties of wet fastness.

310 ,guished by good fastness-to light and very good properties of wet fastness. g l g What I claim is:

1. A tetrakisazo-dyestufi corresponding in its 5 free acid state to the general formula in which R1 and R2 each stand for a benzene radical bound in l-position to the azo-group and containing in d-position a hydroxy group and in 3-position a carboxyl group, R2 stands fora benzene radical to which the two adjacent azogroups are bound in the 1:4-position relatively to one another and which contains an alkyl-O- group in ortho-position with respect-to the amgroup bound to the naphthalene nucleus,- and R4 stands for a benzene radical to which the adjacent azo-groups are bound in the 1:4-position relatively to one another.

2. A tetrakisazo-dyestufi', corresponding in its free acid state to the general formula HOxS- If desired the dyeing in which R2 stands for a benzene radical to which the two adjacent azo groups are bound in the 40 1 zposition relatively to one another and which carries an alkyl-O-group containing up to two carbon atoms in ortho-position with respect to i the azo-groupbound to the naphthalene nucleus,

and R4 stands fora benzene radical to which the adjacent azo-groups are bound in the 1:4-position relatively to one another.

3. A tetrakisazo-dyestuff corresponding in its free acid state to the general formula HOsS- (c) The dyeing is rinsed with cold water, and then after-treated. for /2 hour at 20 C. in a solution, which has been prepared by dissolving 4.5 parts of the water-soluble condensation product of dicyandiamide and formaldehyde, 1.5 parts of copper acetate and 6 parts of concentrated aqueous ammonia solution in 3000 parts of water and adding 2 parts of anhydrous sodium carbonate to HOO the solution containing cupric tetramine acetate. The goods are then rinsed and dried. There is Hu l Hols- Gamein which R2 stands for a benzene radical to which the adjacent azo groups are bound in the 1:4-

position relatively to one another and which car- I ries an alkyl-O-group containing up to two carbon atoms in ortho-position with respect to the azo-group bound to the naphthalene nucleus.

l. A tetrakisazo-dystuff corresponding in its free acid state to the general formula in which R4 stands for a benzene radical to which the adjacent azo-groups are bound in the 1:4-

obtained a deep black dyeing which is distin- '75 position relatively to one another.

I i'zgeoznss v 11 7 '12 5. The tetrakisazo-dyestufl corresponding in its free acid state to theformule, V

6. The tetrakisazo-dyestuff corresponding in its free acid state to the formula.

'7.The tetrakisa-zo-dyestu'fi corresponding in Qff its free acid*state-totheformula REFERENCES CITED .The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,050,913 Anderau Aug. .11, 1936 2,215,087 Schweitzer Sept. '17. 19.40 2,270,675 Stein et a1 Jan. 20, 1942 52,435,356 Kaiser Feb. 3, .1948 

7. THE TETRAKISAZO-DYESTUFF CORRESPONDING IN ITS FREE ACID TO THE FORMULA 